Journal of Physics Special Topics An undergraduate physics journal P4 2 The Destruction of the DS-1 S. Howard-Clark, H. Graham, W. Sainty and S. Kneeshaw Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH November 16, 2017 Abstract In this paper we aim to investigate the demise of the DS-1 (Death Star I) Orbital Battle Station over the planet Yavin in the film \Star Wars: A New Hope" and propose any effects the explosion would have on Yavin IV. Kepler's 3rd law and Pythagoras Theorem are used to find the distance between Yavin IV and the Death Star, showing at the time of the explosion the Death Star is 1:17 × 1011 m away from Yavin IV. The flux density (irradiance) at the surface of Yavin IV is also calculated giving a value of 1:17 × 109 W m−2, which we believe would be more than enough radiation to cause mass extinctions on Yavin IV, even at this extreme distance. 1 Introduction make 4 of its orbit to charge its laser. As we In the film \Star Wars: A New Hope", we know the charge time is 24 hours [1], we assume see the Imperial DS-1 Orbital Battle Station [1] one orbit of Yavin would take the Death Star moving into range of the forest moon of the around 92 hours, and that the Death Star fires planet Yavin [2] to attack the Rebellion hold- when it forms a right angle between itself, Yavin ings on that moon (Yavin IV) [3]. Just as the and Yavin IV. Our final assumption is that the battle station is ordered to destroy the moon, explosion takes 1 second, as this is around the the forces of the Rebel Alliance manage to land difference in time between the first frame of the a critical blow on the hypermatter reactor of the explosion in the film, to the Death Star no longer DS-1, causing it to be destroyed in the result- being visible. ing explosion. We investigate the power output Using the value for energy output of the DS- of this explosion and the effect it would have on 1 from \That's no moon" [4] we can see that the surrounding planet of Yavin and the moon the Super Laser of the DS-1 was capable of out- Yavin IV. putting an energy of 2 × 1032 J. We propose that as the laser is preparing to be fired, the Rebel Investigation assault on the DS-1 causes a reaction that then We make a number of assumptions here to results in that energy feeding back into the core bring the DS-1 into our own reality and to help of the DS-1 causing it to almost instantaneously attribute to the otherwise missing variables that explode as we see in the film. To find out how are not available to the viewer of the film. We the explosion effects Yavin IV, the amount of ra- assume Yavin IV has a composition similar to diation reaching the surface needs to be found. the Earth as both are of a similar diameter. An- To do this the distance between the Death Star other assumption is that the Death Star has to and Yavin IV at the point of firing must first be calculated. the surface of Yavin IV would also be far larger This was done by using Kepler's 3rd law [5], as than the flux density hitting Earth from the Sun. shown in equation (1) to find the orbit of both For reference the flux density from the Sun at the Death Star around Yavin and the orbit of the surface of Earth is equal to 1366 W m−2 [7]. Yavin IV around Yavin. These two distances, ads Therefore the magnitude of flux at the surface of and ayiv can be used with Pythagoras' theorem, Yavin IV is 6 orders of magnitude larger. This equation (2), to find the distance d. At distance kind of radiation would likely destroy any atmo- d, the Death Star forms a right angle between sphere the planet had and boil away any liquid itself, Yavin and Yavin IV. water on the surface, rendering the planet barren and uninhabitable. s a3 It is reasonable to assume that even at a dis- T = 2π (1) µ tance of nearly 1 AU, this explosion would dis- rupt the Yavin planetary system as the explosion 2 2 2 ads + ayiv = d (2) would radiate outwards in all directions, trans- ferring much of the energy produced by the ex- This gives us a value of d = 1:17 × 1011 m, plosion onto any surface it touched, the closest which is very close to 1AU, where µ = GM = of which would be the gas giant Yavin. 3:6×1017 m3 s−2 (where M is the mass of Yavin, 5:54×1027 kg) and the orbital period is given by Conclusion T, in seconds (92 hours for the Death Star and The internalisation of the energy of the DS- 4818 days for Yavin IV). 1 Super Laser into itself would have a disas- To find the irradiance at Yavin IV, the radiant trous effect on the inhabitants of the station, intensity needs to be calculated from the total immediately vaporising everybody on board. It power of the explosion as given in equation (3). would also damage the atmosphere of Yavin IV irreparably as a result of the radiation being d2E P I = = (3) transferred onto the moon, causing mass extinc- dtdΩ 4π tions and the planet to be completely uninhabit- This gives a value of I = 1:59 × 1031 W Sr−1, able. Due to the way explosions travel in space, where P = 2 × 1032 W, the energy dispersed by the remnant matter and shockwave of the DS-1 the explosion in 1 second. Equation (3) can then would radiate outwards in all directions, dispers- be used to calculate irradiance at the surface of ing all remaining energy across the entire system Yavin IV (Fyiv). around it [8]. Icosδ References Fyiv = (4) [1] http://starwars.wikia.com/wiki/Death_Star [Accessed d2 29/9/17] 9 −2 This gives a value of Fyiv = 1:17×10 W m , [2] http://starwars.wikia.com/wiki/Yavin [Accessed 29/9/17] where d is taken from equation (2) and I is taken [3] http://starwars.wikia.com/wiki/Yavin_4 [Accessed 29/9/17] from equation (3) and δ = 0o (the angle between [4] D. Boulderstone, C. Meredith, S. Clapton, A2 8 That's No the moon and the Death Star on the plane of the Moon, PST9(1), (2010) solar system). [5] https://en.wikipedia.org/wiki/Orbital_period [Accessed Discussion 29/9/17] Consolidating all of the above calculations to- [6] https://www.ess.uci.edu/~yu/class/ess55/lecture.3.energy. pdf [Accessed 01/11/17] gether shows us that the destruction of the DS- [7] https://www.quora.com/ 1 would be an event of extinction level propor- What-would-explosions-in-space-look-like [Accessed tions, with a power output six orders of magni- 29/9/17] tude more than the Sun. The flux density hitting.